Aspirin is well known among ordinary people to be an effective anti-coagulant drug that protects those who use it regularly form cardiovascular diseases and it is so “popular” among the elderly that millions of them consume it daily for this particular reason. Furthermore, it is an OTC (Over The Counter) drug widely preferred to control pain –especially headache-inflammation and fever, but, to be scientifically accurate, it must be pointed out that aspirin has medically-proved benefits regarding the secondary prevention of cardiovascular events. However, its role in the primary prevention of cardiovascular events in elderly is yet to be sufficiently established. In other words, Does Aspirin have a protective role against cardiovascular diseases in healthy elderly? In this new study from The New England Journal of Medicine, scientists seek to know if aspirin has advantages that outweigh its disadvantages.
As the aforementioned stated, aspirin has noticeable benefits but it can increase the likelihood of major hemorrhage. Thus, a group of scientists (led by J. J. McNeil who is a M.M.B.B, Ph.D., and head of the Department of Epidemiology and Preventive Health at Monach University, Melbourne, Australia and A. A. Murry, M.D.) conducted this randomized, double-blind, placebo-controlled clinical trial, in which 19,114 persons were enrolled, 9525 of them received aspirin and 9589 received placebo. Those who participated were community-dwelling elderly from the USA and Australia and had a median age of 74 years, nearly have of them were women (to be precise, women were 56%).
The persons to be eligible for that trial were required to be free from many specific diseases, including of course overt coronary heart disease, cerebrovascular disease and other medical conditions such as dementia, advanced stages of high blood pressure and other vascular and hematological diseases. Needless to say, those who could not take aspirin for any reason were not enrolled and the same goes for those who were taking anti-coagulant or anti-platelet drugs other than aspirin.
The participants took 100 mg of enteric-coated aspirin daily. After a median follow-up of 4.7 years, the results were quite interesting.
Although that aspirin did have advantage over placebo, it was a small advantage. Statistically speaking, there were 10.7 cardiovascular events per 1000 person-years in the aspirin group and 11.3 per 1000 person-years in the placebo group, which is obviously not a remarkable difference. On the other hand, there are a lot to compare when talking about disadvantages, the hemorrhage.
Cumulative Incidence of Cardiovascular Disease
There were 8.6 major hemorrhage events per 1000 person-years in the aspirin group compared to 6.3 per 1000-years in the placebo group. Moreover, to get it right, one should dive into the details. Risks of gastrointestinal bleeding were higher in the aspirin group. In addition, intracranial bleeding risks were also less in the placebo group, and to mention more facts, the risk of all subtypes of this type of bleeding –intracranial bleeding- was higher with aspirin than with placebo (subdural and subarachnoid hemorrhage etc…).
Cumulative Incidence of Major Hemorrhage
Therefore, the study showed that aspirin does not have such a better result relating to cardiovascular events compared to placebo but unfortunately, it increases the risk of major hemorrhage noticeably. Additionally, to interpret the outcomes, one should put in the back of his/her mind that the trial participants had a cardiovascular disease rate way lower than expected due to two factors: decreasing of the rate of cardiovascular disease itself in the aforementioned countries (USA and Australia) and because the participants enjoyed a good health, relatively speaking.
It worth to point out some limitations of this study mentioned by the researchers. For example, by the end of the trial, third of the participants did not adhere to it, which means that the real estimation of the aspirin’s benefit may be higher. Anyway, this adherence rate was sufficient to indicate clearly to a high bleeding risk due to aspirin.
Considering the results that are mentioned above, one can easily conclude that low-dose aspirin when used by healthy elderly has an insignificant advantage over placebo as it did not lower the risk of cardiovascular disease substantially but it resulted in a considerably higher risk of major hemorrhage.
J. J. McNeil and others, Effect of Aspirin on Cardiovascular Events and Bleeding in the Healthy Elderly, N Engl J Med 2018; 379:1509-1518